Thunderherd Migration is a uncommon Sorcery card from Rivals of Ixalan (RIX), collector number 149. Current market price: $0.16 (foil $1.05), TCGplayer market prices via Scryfall.
As an additional cost to cast this spell, reveal a Dinosaur card from your hand or pay {1}. Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.